问日期选择器未显示正确的字段

EN

 // This is a manifest file that'll be compiled into application.js, which will include all the files
    // listed below.
    //
    // Any JavaScript/Coffee file within this directory, lib/assets/javascripts, vendor/assets/javascripts,
    // or vendor/assets/javascripts of plugins, if any, can be referenced here using a relative path.
    //
    // It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
    // the compiled file.
    //
    // WARNING: THE FIRST BLANK LINE MARKS THE END OF WHAT'S TO BE PROCESSED, ANY BLANK LINE SHOULD
    // GO AFTER THE REQUIRES BELOW.
    //
    //= require jquery
    //= require jquery_ujs
    //= require jquery_ui.all
    //= require_tree .

$(function() {
    $(".datepicker" ).datepicker({dateFormat: "yy/mm/dd"});
});

    /*
     * This is a manifest file that'll be compiled into application.css, which will include all the files
     * listed below.
     *
     * Any CSS and SCSS file within this directory, lib/assets/stylesheets, vendor/assets/stylesheets,
     * or vendor/assets/stylesheets of plugins, if any, can be referenced here using a relative path.
     *
     * You're free to add application-wide styles to this file and they'll appear at the top of the
     * compiled file, but it's generally better to create a new file per style scope.
     *
     *= require_self
     *= require_tree .
     *= require_jquery.ui.all
    */

And in the view:

<%= form_tag url: {action: 'do_something'} do |f| %>
        <%= text_field_tag :birth_date, '', :class => "datepicker" %>
        <%= submit_tag "Do something man!"%>
        <% end %>